The present invention relates to footwear construction, and more particularly, to a sole construction having independently inflatable compartments.
Footwear having one or more in fluid-inflatable sole compartments is known in the prior art. One sole construction, typified by U.S. Pat. No. 3,120,712 to Menken, includes an insole and an outsole which are joined at their peripheral edge regions by a relatively wide supporting wall member. The elongate inflatable space formed between the two soles contains a rubber bladder which is inflatable to a desired sole cushion pressure. Alternatively, the sole construction may include a pair of longitudinally spaced and independently inflatable sole compartments corresponding to heel and ball foot regions as disclosed in U.S. Pat. No. 2,605,560 to Gouabault and U.S. Pat. No. 508,034 to Moore.
A characteristic of such sole constructions known in the prior art is that the inflatable sole regions are substantially uncushioned with the air compartments deflated, such as might occur by air leakage. The deflated compartments would then be felt as uncushioned pockets in the sole, producing foot fatigue and discomfort over an extended period of wear.
One object of the present invention is to provide, in a sole construction having a plurality of independently inflatable compartment, elastomeric support members in the compartments for providing auxiliary cushioning.
Another object of the invention is to provide such a sole construction having an independently inflatable compartment corresponding to the arch region of a foot.
Yet another object of the invention is to provide, in such a sole construction, an interchangeable tread sole.
The sole construction of the present invention provides localized variable cushioning in footwear having a top attached to an inner sole. The construction includes an outer sole and a flexible wall structure joining the peripheral edges of the inner and outer soles to form an enclosed space therebetween. This space is partitioned into fluid-tight inflatable compartments corresponding substantially to the heel, arch and ball regions of a foot. The compartments are independently inflatable to desired fluid pressures by suitable valving associated with each of the compartments. Resilient support members in the compartments provide cushioning weight support between the inner and outer soles when associated compartments are in fully or partially deflated conditions.
In one embodiment of the invention, the support members are constructed to receive fasteners used in fastening an interchangeable tread sole to the outer sole in the construction.
These and other objects and features of the present invention will become more fully apparent when the following detailed description of preferred embodiments of the invention is read in conjunction with the accompanying drawings.